V. F. Lavrushin

Dipole moments of thiophene analogs of chalcones and their vinylogs

The dipole moments of 25α, β unsaturated ketones of the thiophene series are measured in benzene at 25°, and their most probable coplanar conformations established. For the systems studied it is shown that, in the static state, the 2-thienyl group exhibits an electron-donating effect, greater than those of 2-furyl and phenyl. Introduction of electron-donating and electron-accepting substituents into the molecule of 1-(thienyl-2)-3-phenylpropenones as well as shift of the carbonyl group away from the aryl one towards the heterocyclic ring, leads in general to an increase in dipole moment. A linear relationship is found for the changes in dipole moment of isomeric thiophene ketones due to electron-donating substituents. Dipole moments of propen-3-ones correlate satisfactorily with Hammett σ parameters for substituents, and intermolecular distances.

Synthesis of chalcone analogs and derivatives of 2-pyrazoline from 3-formylindole

By the crotonic condensation in an alkaline medium of 3-formylindole with various aromatic and heterocyclic methyl ketones, and also with cyclopentanone, cyclohexanone, and 1,4-diacetylbenzene, we have synthesized nineteen α,β-unsaturated ketones. The majority of them were characterized as the 2,4-dinitrophenylhydrazones, the absorption maxima of which in chloroform are given. Some considerations are expressed concerning the reactivity of 3-formyl- and 3-acetylindoles. Ten 3-aryl-1-phenyl-5-(indol-3-yl)-2-pyrazolines and their analogs with a 3-heterocyclic residue have been synthesized by the reaction of 3-aryl-1-(indol-3-yl)propen-3-ones and the corresponding analogs with phenylhydrazine. Some of the compounds synthesized possess a bright luminescence.

Synthesis of unsaturated diketones and ?2-pyrazoline derivatives from terephthalaldehyde

Abstractα,β-Unsaturated diketones were obtained by the condensation of terephthalaldehyde with aromatic and heterocyclic methyl ketones. The reaction of the diketones with phenyl-hydrazine gave 1,4-bis(1-phenyl-3-aryl-Δ2-pyrazolin-5-yl)benzenes.

Synthesis of unsaturated ketones and derivatives of 2-pyrazoline containing an indole nucleus

The crotonic condensation of 3-acetylindole, its N-methyl derivative, 3-formyl-1-methylindole, and 3-formyl-6-nitroindole with various aldehydes and methyl ketones in an alkaline medium has yielded a number of unsaturated ketones, some of which have been characterized as their 2, 4-dinitrophenylhydrazones. The reaction of some of these unsaturated ketones with phenylhydrazine has yielded derivatives of 1-phenyl-2-pyrazoline, which possess luminescent properties.

Synthesis of chalcone analogs containing a pyrrole ring

Crotonaldehyde-type condensation in alkaline medium of 2-acetylpyrrole or pyrrole-2-aldehyde with aromatic or heterocyclic aldehydes and methyl ketones gives a number of hitherto undescribed pyrrole analogs of chalcone, and their 2, 4-dinitrophenylhydrazones are prepared.

Electronic spectra of α,β-unsaturated ketones — Indole derivatives

The electronic spectra of (3-indolyl)-, (1-methyl-3-indolyl)-, and (6-nitro-3-indolyl)-substituted α,β-unsaturated ketones were measured and interpreted. 3-Indolyl and N-methyl-3-indolyl substituents have a considerable bathochromic effect as compared with the phenyl group in the investigated systems as a consequence of the electron-donor effect, which surpasses that for 4-anisyl, 2,4-dimethoxyphenyl, 2-furyl, 2-thienyl, and 2-selenienyl and differs only slightly from 2-pyrrolyl. The introduction of electron-donor substituents into the p position of the benzene ring of 1-(3-indolyl)-3-phenyl-1-propenone causes a red shift of the long-wave absorption band, the difference in frequencies of which correlates with the Hammett σ substituent constants. Except for compounds containing a nitro group,1-(3-indolyl)-3-aryl-3-propenones and their N-methyl derivatives fluoresce well in alcohol with λmax >475 nm.

Electronic absorption spectra of the cations and anions formed from pyrrole analogs of the chalcones

The electronic absorption spectra of 29 pyrrole analogs of the chalcones have been studied in solutions of strong acids and alkalies, in which the corresponding cations and anions are formed. It has been shown by means of the IR spectra that the protonation of the pyrrole chalcones takes place at the carbonyl group. Considerations are given of the structure of the organic cations and anions studied and of the characteristic features in the change in their coloration as a function of their chemical structure. Satisfactory correlations have been found between the shift of the absorption frequency of the long-wave band which takes place at the transition from a neutral solution (molecules) to an acid solution (cations) or to an alkaline solution (anions) and Hammetts o constants. Three 3-(4-halophenyl)-1-(2-pyrryl)propenones not previously reported in the literature have been synthesized.

Ultraviolet absorption spectra of chalcone analogs containing a selenophene nucleus

The UV absorption spectra in solutions in hexane and ethanol of chalcone analogs containing, apart from 2-selenienyl, the following heterocyclic radicals-2-furyl, 2-thienyl, 2-pyrryl, 2- and 3-pyridyl, and 2-quinolyl-have been measured and discussed. Considerations on the electronic influence of the heterocycles have been put forward and the Hammetts parameters have been evaluated for some of the radicals.

SYNTHESIS OF CHALCONE ANALOGS - 4- AND 5-NITROPYRROLE DERIVATIVES

Nitropyrrole analogs of chalcone have been synthesized by aldol condensation in basic medium from 5-nitropyrrole-2-carboxaldehyde, 4- and 5-nitro-2-acetylpyrrole, and the corresponding aromatic aldehydes and methyl ketones; their 2, 4-dinitrophenylhydrazones have been obtained. Some considerations are expressed concerning the reactivity of pyrrole-2-carboxaldehyde, 2-acetylpyrrole, and their nitro derivatives.

Electronic spectra of the ionic forms ofα,Β-unsaturated ketones — Indole derivatives

The formation of the corresponding organic cations and anions was shown on the basis of data on the electronic absorption spectra of 33α,Β-unsaturated ketones-indole derivatives — in solutions of strong acids and bases. Observations regarding the dependence of the colors of the investigated ionic forms on the chemical structure are made.